I just bought a 93 FD and it hit fuel cut under load at 4000 rpm in 4th gear. Seems to be fine in 1st, shutters a bit in 2nd and pulls good in 3rd and then cut out hard in 4th around 4000. I'm new to this and spent everything I had buying the car. The brakes were shot so I spent the little I had on rotors and pads along with an HKS BOV. Mt question is can I set the BOV so that it won't overboost and hit fuel cut? I know I really need to get a new ECU or an F-con but can't right now. Will the BOV keep everything in check for now?

 

Unless it's leaking, there is no way a BOV can effect boost levels. What are the mods on the car?

The proper way to lower the boost (if that really is your problem, it doesn't sound like you have a boost gauge) is to install a manual or electronic boost controller. If you don't have the cash for one, sell your worthless BOV (the stock ones work fine) and get a Profec B with the proceeds. Or install a manual "home depot" boost controller and get a boost gauge.

If you can't afford a $400 ecu (the price of a used M2 or Pettit ecu), you shouldn't have bought this car. BTW, a new engine will be in the range of $4-5k if you blow it, so I suggest you pony up a little cash and do something...

 

Just connect the vaccum line for the BOV to the nipple on the intake pipe of your front turbo. That way you won't be overboosting.

 

BOVs should not be used to control boost. Leaking out the air can cause the turbos to overspin, though probably most people with this car have had boost leaks at some point without killing the turbos, so that warning doesn't hold much water. Even so, creating a leak is not a good solution in general for various reasons, and BOVs aren't supposed to leak boost when you are on the throttle under any conditions anyway. You are probably thinking of a different device...

A "pop-off" valve is designed to prevent overboosts by bleeding air out, but they aren't really a boost control device in the normal sense -- just a failsafe if something goes wrong. If everything is setup and functioning correctly, you shouldn't be opening the pop-off valve.

Search for info on "pills", which are the little orifices in the lines to the pre-control and wastegate actuators. If the hole is too small, you will get more boost than you want. Later cars had the orifices built into the nipples, rather than stuffed into the hoses. It is possible that you got new turbos with the orifices in the nipples, yet you also have them in the lines. That would lead to overboosting, as would a number of other things like opening up the intake and exhaust, etc.

What boost level are you hitting? It is possible that there is some other problem rather than the ECUs boost-triggered fuel cut.

-Max

 

you definately need a boost gauge

 

Thank you all for answering my post!! rynberg dude you were a little harsh. But I value your opinion. I had to borrow cash to buy the car and I'm strapped!! I just don't want to blow my motor. maxcooper, I'll search pills for sure and see what I have going on with my car.
rynberg, this car has a down pipe with a high flow cat and a racing beat cat back. So I would think that's what's causing it to overboost. My friend made a manual boost controller for his Supra and it worked great for turning up the boost. I asked him if we can do that with my car and he said it wouldn't turn it down only up. I don't know. If this will work I'll get it done tomorrow!! How much does an Apexi boost controllor cost? I would think a boost gauge wouldn't be to expensive. Anyone else with suggestions??

 

You definitely need a boost gauge.

If you remove the pills (assuming yours are removable, and not the orifice-in-the-nipple type), you will be able to riase or lower your boost with a manual controller.

-Max

 

Cool thanks max, I'll look into it tomorrow.
I'll get a boost gauge

 

Rxdriver:

I came across as harsh because I don't like to pull punches. It is the TRUTH that if you had to borrow money just to get the car and you are too strapped to afford a $300 Profec B boost controller (or less for a used one), you should not own this car. That's not being harsh and it's not being mean, it's just being truthful.

The other reason I came across as harsh is because you say you are strapped for cash yet bought a $200+ BOV. An aftermarket BOV is not necessary for these cars and is a totally worthless mod (unless you go single turbo). You could have easily spent that cash on a boost controller or other maintenance items.

Sorry if I still sound like an ******* but I hate it when these cars are neglected and it sounds like your car will go down that road -- not because you aren't responsible or don't care -- but because you simply don't have the funds. I don't mean to single you out but these cars take a substantial financial committment. If you ask any of the long time owners who actually take care of their car, you will hear the same thing.

Good luck with your car, get your boost issues under control to avoid a blown engine.

 

rynberg, so what your telling me I should do is send back the BOV and buy a boost controller. I haven't even received the BOV yet. Where can I get a good deal on a profec B boost controller? I'll take care of her I promise!!

 

Jason at the rx7store.net has a very good price on the Profec B. Purchasing from the store supports the forum too.

Good luck.

 

maxcooper

Your good!! I took the pill out and installed a manual boost controller. Right now It's 100% open. My car is like a f*%ken jet taking off. I swear I owned an S2000 before this car and there is no comparison!! It still hits fuel cut at a low rpm in a high gear. The guy I bought the car from said it was a PFSC rebuild motor with intake porting. Now I believe!! I swear the thing will run 12's the way it sits. I ordered a boost gauge so I can see better what's going on. I may be getting a boost spike causing fuel cut. After the boost gauge I'm saving for a F-con. I figure why get an aftermarket ECU tuned to my mods when I plan on adding more in the future. One other question I have is what is a good aftermarket intake.

 

This doesn't sound good. Not good at all.

 

I totally agree. He is already hitting fuel-cut and wants to install an intake?

RxDriver:

Get a Pettit or M2 ecu. You can get them tuned for your mods. Pettit only charges $40 or so to change out the chips if you change your mods. None of the piggy-backers (F-con, Apexi S-afc) work worth the damn for your problem.

Seriously, listen up. You are going to blow your motor if you continue down the path you are going down.

 

LOL, I'll be carefull!! An F-con won't do the job??
****!! OK, I'm listening, I'll get a pettit ECU. Should I just buy one new directly from Pettit?? Because if I buy a used one how will I know it works with my mods?
Thanks for all your help guys, I need it

 

I am kinda new to the forum, but isn't he going to blow his engine? He has a dp, mp, and catback with no computer or fuel upgrades. If he gets a intake before he gets a fuel computer I would think he is sure to blow his motor. I would search the forum for staged upgrades, or reliability before you even continue driving the car hard.

 

I'm not going to get an intake until after I get an ECU!!

 

What the hell...?!

 

I found a Pettit ECU for $475 shipped, is this a good deal?

 

That may be a bit on the high side but looks pretty fair. Is it tuned for your mods?

 

Yes I called Pettit and they said it would be fine. They said even if I added an intake it would be fine. Have you upgraded your fuel injectors??

 

Nope, that's coming later this summer. Although I may just wait until I do an engine rebuild, which I imagine will be in the next 9 months-year. You can run 12 psi on the stock injectors for daily use. You can even run 14 psi on the stocker but that is pushing the limits of the fuel system to the brink.

 

Well he said he is running a high flow cat which will add more constriction than a straight through midpipe so as long as he keeps his boost at the stock level of 10 he would be ok with those mods but anything above 10 and watch out. Pettit only offers two different ECU's(chips) limited and unlimited, the chips aren't specifically "tuned" to exact mods, the liimited works for light modding and the unlimited for more complex mods, except single turbo of course which I have heard they can work temporarily. Anyways, back to the point, my advice would be to read up on these cars, get a Pettit ECU if you are unable to keep your boost safely below 10psi or if you plan on future bolt on mods. Also if this engine truely is a ported motor you really need an ECU asap, good luck.

 

Oh and send that friggin' BOV back and use the money toward a boost gauge, ECU and some type of boost controller, be it manual or electronic.

 

I am getting the Pettit limited ECU ASAP. I found a used one for $475 shipped. I also installed the manual boost controller and left it wide open. This helped a lot. Gauges are next!! I'll send the BOV back.